centerboard

[kpbroughton]

hopping to lift suzy bee off it,s trailer this week to fix the leaking centerboard trunking . the centerboard has all ways stuck in the trunking and was thinking of changing it for a metal one any body have any thoughts on this.

[JonLee]

I mulled aluminum when I replaced my centerboard, but after a few consultations with JCH and much scoping, mulling, contemplating, and philosophizing, I instead decided to go to a board made of 1/2 plywood, covered with 2 layers of 6 oz. glass cloth. I also increased the size of the lead filled area on the board. Probably the biggest challenge of going that route was dealing with the pendant, which is almost as big as the board is wide. Rather than try to bore a hole like in the regular board, I ended up routing out a channel in the board, pre-tying a knot in the end of the pendant, laying the pendant in the channel and filling in/fairing the channel with epoxy.

[riverron]

It looks like two examples of centerboard issues. Can you tell me what is happening to the centerboards that you need to replace them?

thanks

[JonLee]

Two different causes. If I remember correctly, I think Suzy B got damaged during an unexpected grounding.

On Solitude III, at the end of my build I was rushing in order to get the boat done in time to take it to the 2012 Wooden Boat Festival in Port Townsend. In my hurry, when I was sanding the hull, I sanded through the fiberglass/epoxy in two spots right on the lip of the centerboard trunk. I didn't catch it at the time, (didn't do a through inspection prior to painting). Over about two years, water seeped into the wood through the breach in the fiberglass/epoxy sheathing, swelling the plywood and jamming the centerboard. Ultimately, I ended up stripping the paint in the area and resealing, reglassing, and repainting. The swollen wood wasn't going anywhere, so I also had to replace the board with a narrower one.

The basic design is sound, so don't worry about anything other than being conscientious about your build.

Basically, don't panic.

[riverron]

Thanks Jon! I do start to worry when I hear about issues and want to avoid them. I will continue the course.

[kpbroughton]

]The Suzy B did get damaged during an unexpected grounding but that only brought the centerboard trunk problem to light. Water seeped into the wood through lower part of the trunk/keel and started to fill the bilges with water , had to cut out the hole port side of trunking and replace with new wood not a small job

[riverron]

]The Suzy B did get damaged during an unexpected grounding but that only brought the centerboard trunk problem to light. Water seeped into the wood through lower part of the trunk/keel and started to fill the bilges with water , had to cut out the hole port side of trunking and replace with new wood not a small job

Glad you got it fixed! What are your thoughts on mixing graphite in the epoxy coatings on the centerboard itself? I noticed some othe builders did this?

[JonLee]

I am not sold on the idea. Carbon cloth would add strength, but without the fibers I am not sure what you are getting besides some abrasion resistance. And if you do the silica/epoxy "armor" on the leading edge of the board per the instructions, you are plenty tough on the one part of the board that actually could get abraded. Maybe they thought it to "reduce friction" between the board and the trunk? Still of dubious value to me, since a) the board is 1/4" narrower than the trunk, so it's doesn't exactly need to be a well-oiled machine to work, and b) you are already sanding the board to a "smooth as marble" finish, so how much of a reduction in friction do you really think you are going to get?

Plus, you never get to see the board in operation, so how could you show everybody how cool it looks?

Now, on the topic of abrasion resistence, one thing that I thought about doing, but didn't, but kinda wish I did, would be to run a strip of aramid (Kevlar) along the bottom of the keel when fiberglass in the bottom. Aramid is a bit of a pain to work with, since it doesn't like being sanded or cut, but it might be worth the small add hassle...it seems like it would make a heck of a keel shoe.